Add gitlab-ci and dockerfile to main branch

.gitlab-ci.yml

+image: docker:19
+
+variables:
+  DOCKER_DRIVER: overlay2
+  DOCKER_TLS_CERTDIR: ""
+
+services:
+  - docker:dind
+
+stages:
+  - build
+  - push
+
+# template for docker login
+.before_script_template: &docker-login
+  before_script:
+    - echo "$CI_REGISTRY_PASSWORD" | docker login -u "$CI_REGISTRY_USER" --password-stdin $CI_REGISTRY
+
+# build and push image
+build-docker:
+  <<: *docker-login
+  stage: build
+  script:
+    - docker pull $CI_REGISTRY_IMAGE:latest || true
+    - docker build --pull -t $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA .
+    - docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA
+
+push-latest:
+  <<: *docker-login
+  stage: push
+  variables:
+    # we don't need git
+    GIT_STRATEGY: none
+  script:
+    # reuse previously pushed image
+    - docker pull $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA
+    - docker tag $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA $CI_REGISTRY_IMAGE:latest
+    - docker push $CI_REGISTRY_IMAGE:latest
+  only:
+    - master
+
+push-tag:
+  <<: *docker-login
+  stage: push
+  variables:
+    GIT_STRATEGY: none
+  script:
+    - docker pull $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA
+    - docker tag $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_NAME
+    - docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_NAME
+  only:
+    - tags
+

Dockerfile

+# build stage
+FROM node:lts-alpine as build-stage
+WORKDIR /app
+COPY package*.json ./
+COPY yarn.lock ./
+RUN yarn
+COPY . .
+RUN yarn run build
+
+# production stage
+FROM nginx:stable-alpine as production-stage
+COPY --from=build-stage /app/dist /usr/share/nginx/html
+COPY nginx.conf /etc/nginx/nginx.conf
+EXPOSE 80
+CMD ["nginx", "-g", "daemon off;"]

nginx.conf

+user  nginx;
+worker_processes  1;
+error_log  /var/log/nginx/error.log warn;
+pid        /var/run/nginx.pid;
+events {
+  worker_connections  1024;
+}
+http {
+  include       /etc/nginx/mime.types;
+  default_type  application/octet-stream;
+  log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
+                    '$status $body_bytes_sent "$http_referer" '
+                    '"$http_user_agent" "$http_x_forwarded_for"';
+  access_log  /var/log/nginx/access.log  main;
+  sendfile        on;
+  keepalive_timeout  65;
+  server {
+    listen       80;
+    server_name  localhost;
+    location / {
+      root   /usr/share/nginx/html;
+      index  index.html;
+      try_files $uri $uri/ /index.html;
+    }
+    error_page   500 502 503 504  /50x.html;
+    location = /50x.html {
+      root   /usr/share/nginx/html;
+    }
+  }
+}